Friday, January 29, 2010
Less Weight Analystics
Yesterday's "No More Spaghetti Bolognese" has a quote from João Correia in which he says, "During the rides you’d be going up a hill and pretty soon you’re dropped, you’re gone, you’re not even in the group anymore.”
Personally, I'm terrible about the analytics as they relate to cycling. I'm more of a just go out and ride kind of guy. No HRM, no computer, no Garmin, no Powertap, etc. Nevertheless, I was curious to see what I could find out about how significant weight loss is and found http://www.analyticcycling.com/ where you can find modeling tools to determine all kinds of things.
They have a calculation model for determining the benefits from less weight here. Accompanying that calculation model is this text (and the chart at the top of this article):
Less weight going up a slope means faster times. How much faster?
Suppose one is considering buying a new, light-weight frame or going on a diet. What is the benefit from having less weight? How much time would be saved over a given distance on a specified slope? How much more distance would be covered in a given time?
Two riders, identical except that one has less weight than the other, ride a given distance up a hill. The the calculation gives the distance and time between the riders as the lightest rider reaches the given distance.
The plot shows the benefit from less weight when riding up a hill. The range of the plot is from -10% to +10% grade and from 0 to 5 kg less weight. The table gives specific values for the given speed.
Note that large changes may produce mathematical results, but may not have real-world meaning. Keep changes small.
"Negative values for improvements" show that weight is an advantage going down a hill. The plot shows that weight is more of a penalty going up hill than an advantage going down.
Example: Benefit From Less Weight
This Much Less Weight 5 kg
Over This Distance 2000 meters
On Hill of Slope 0.03 Decimal
Faster by 8.69 s
Ahead by 64.82 m
Frontal Area 0.5 m^2
Coefficient Wind Drag 0.5 Dimensionless
Air Density 1.226 kg/m^3
Weight Rider & Bike 75 kg
Coefficient of Rolling 0.004 Dimensionless
Power 250 watts
Wow, those seconds can add up fast on the very long climbs in Italy!
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